1. Field of the Invention
The present invention relates to a conductive resin molded product having an insulating skin produced by a composite consisting of nonconductive resin and conductive material, and relates to a method for producing the same.
2. Detailed Description of the Prior Art
According to a conventional method, nonconductive resin is blended with conductive material such as carbon black and carbon fiber, or metal powder and metal fiber and the composite is then molded to produce a conductive resin molded product. (For example, refer to Non-patent literature 1 below).
Moreover, some conductive molded products are produced by injection-filling a mold with conductive resin in which a conductive compounding material such as metal fiber or metal powder is blended with nonconductive resin. (For example, refer to Patent literature 1 below).
Non-patent literature 1: Ebihara, “Handbook of New Polymer Materials” P. 69 to 74, Maruzen Co., Ltd. September 20, 1989.
Patent literature 1: The Japanese Patent Laid-Open No. 1993-131445, P. 5.
Conventionally, a conductive resin molded product has been produced by blending a conductive compounding material with a nonconductive resin to provide a resin with conductivity. However, as described in Non-patent literature 1 and Patent literature 1, most of the conventional conductive resins have adopted carbon black, carbon fiber, metal powder, or metal fiber which has remarkably large particles compared with the molecules of the resin as the conductive compounding material. When such conductive compounding material is blended to the extent that the resin is able to have conductivity, the molded product has conductivity even on its surface; therefore, insulation treatment of the surface is necessary depending on its use.
Moreover, the shape of the molded product tends to be restricted since the properties of the resin such as lightweight, flexibility, moldability, and processability are deteriorated, causing a hindrance in the production of the molded product by injection molding and lowering mechanical strength and the like. As a result, there is a problem in adopting the above-mentioned technique to a product with a complex shape, even when used as a magnetic wave shield material.